Armature for electro-magnetic relay



Jan. 12, 1965 LE ROY HOGAN 3,165,607

ARMATURE F OR ELECTRO-MAGNETIC RELAY Filed Aug. 11, 19 1 J J FIG. 1

26 i4 15 p J mp m ED ARRMGEME T7" X Q H' 2' 26' men ART ARRANGEMENT P 5' C f 24' 20' A 'I INVENTOR LE ROY HOGAN FIG.3 BY 7 ATTORNEY United States Patent ARMATURE. FOR ELECTRO-MA'GNETIC RELAY Le Roy Hogan, E ssex- Junction, Vt assignor to International Business Machines Corporation, New York,

'NLY.,' a corporation of New York Filed Aug; 11,1961, Ser. No. 130,842

4 Claims. (Cl. 20087) v This invention relates to electro-magnetic relays and more particularly to an improved electro-magnetic relay which embodies a linkage arrangement between the armature and contact members whereby faster operate times are obtained and the useful life of the relay is prolonged because wear is reduced.

It is known to provide a compact relay comprising an actuator which provides an operating connection between an armature and one or more contact members, and wherein the armature and contact members are generally parallel to each other and disposed at right angles to the operating axis of the electro-magnet. The armature and contact members are pivoted at their adjacent ends; and hence the degree of movement of both the armature and contact members will'increase or decrease in direct proportion as the actuator is positioned at a greater distance or lesser distance, respectively, from said pivot points. As the working gap of the armature increases, the operate time of the relay increases, being a function of the square of said gap; also, the amount of power required to attract the armature increases substantially as the square of said gap-increases. If the electro-magnet is moved toward the armature and the actuator is moved toward the pivot points to reduce the gap and armature travel in an effort to reduce the operate time, the degree of permissible travel of the contact member will be correspondingly reduced, and may be reduced to a value insuflicient to insure positive make and break of the contact member with the contact points. Also, adjustment of the actuator toward the pivot points reduces the moment arms of the armature and contact members and hence undesirably reduces the efliciency of the linkage connection therebetween. Thus, the working gap of the armature must be maintained at at least a certain optimum minimum value to provide suflicient permissible movement of the, contact members and yet assure the required degree of efiiciency of the linkage.

" The principal object of this invention is to provide an improved electro-magnetic relay embodying a linkage arrangement between the armature and contact members whereby the armature working gap may be reduced without having to reduce the degree of permissible-movement of the contact members, thereby to provide faster operate times than heretofore achieved and also reduce contact bounce and wear to achieve longeruseful life.

Another object is to provide an improved electromagnetic relay of the permissive make type. The term permissive make is used to connote those relays in which the contact members are resiliently biased toward fired contact points, and an actuator connected to the armature positively holds each contact member away from a contact point to break contact and frees such contact member -to permit it to make contact with such each contact member are pivoted near their respective non-adjacent ends (rather th an near their respective adjacent ends An actuator, which provides a lost-motion type operating connection between the armature and each contact member, is so disposed that upon attraction of the armature the free end of the armature will move through a relatively small distance and, through the actuator, move thefree end. of each contact member through a greater distance. Thus, for a given degree of permissible movement of each contact member, the working gap of the armature can be effectively reduced, resulting in a lower final velocity on make and break and thus a reduced degree of contact bounce. The actuator is positioned relative to the armature to provide an eflicient leverage connection therewith, whereas the actuator is positioned somewhat closer to the pivot point of the contact members resulting in a somewhat less eflicient leverage connection therewith in order to reduce the moment arm and hence the degree of rubbing frictional movement between the contact members and the actuator. The reduction in contact bounce and in rubbing friction desirably increase the useful life of the relay; and the reduction, in the working gap of the armature results in a desirable reduction in the operate time of the relay.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawing. 7

In thedrawing: v

FIG. 1 is a side elevation view, partly in section, of a relay embodying the invention; 7

FIG. 2 is a diagrammatic view showing the relationship of the fulcrum or pivot points of the armature and contact members with each other and with the actuator in the improved relay shown in FIG. 1; and

FIG. 3 is a diagrammatic view showing the relationship of the fulcrum or pivot points of the armature and contact members with each other and with the actuator in an electro-magnetic relay of known design.

As shown in FIG. 1 of the drawing, the relay embodying the invention comprises an electro-magnet, preferably in the form of an energizing winding 10 around the center leg of an E-type core 11 of magnetic material. The core is adjustably secured to a U-shaped base 12 of insulating material, such as by screws 13 which pass through elongated slots in the parallel sides of the base and through threaded bores in the respective outer legs of the core. 7

A fiat armature 14 of magnetic material is rockably supported by being confined, at a point near its one end, between the beveled end of one outer leg of core 11 and a beveled shoulder 15 provided by the base 12. A helical ;spring 16 disposed in a bore 17 in the base acts near the said one end of armature 14 to bias the latter counterclockwise relative to its support or fulcrum point at 15.

A plurality of contact members 20 (only one of which is shown) are insertable through respective recesses 21 in the left side of the base 12 and disposed in spaced sideby-side relation in a transverse direction, as viewed in FIG. 1. As illustrated, each contact member 20 is in the form of a hairpin-like spring element having two connected generally parallel wires or legs 22, 23 which are inherently biased apart. Each contact member 20 is rockably supported or fulcrumed at 24 by having its wires pass through closely spaced openings in a respective common insert 25. The fulcrum point 24 is near the free end of the armature; and the wires 22, 23 project generally toward point 15, with each wire 22 being spaced elongated slot or window 27 in the actuator 26, such that the actuator will provide a lost-motion type operating connection between the armature and the wires of each 3 contact member at points intermediate their respective ends. Adjacent its free end each wire 22 is adapted to contact a respective normally open contact 28; and adjacent its free end each wire 23 is adapted to contact a respective normally closed contact 29. The contacts 29- are substantially straight, and the contacts 28 are hooklike, so as to present spaced contact points which are different distances from the armature'14, the contact point of contact 28 being nearer to the armature than that for contact 29.

A locating stud 30 projects from the base 12 a considerably greater distance than the male prongs of each common insert 25, normally open contact 28 and normally closed contact 29, and the clips '31 (only one of which is shown) secured to the respective lead wires of the winding 10. This locating stud merely facilitates locating the relay assemblage in the proper position prior to plugging it to a connector (not shown).

In operation, upon energization of winding 10, the armature 14 is attracted toward the center leg of the core 11, such that its free end engages the usual residual shim or spacer 32 of insulating material. As the armature raises the actuator 26, the lower wall 33 of each slot 27 will contact a corresponding wire 23 and shift the latter away from normally closed contact 29 to break the electrical connection between said contact and the common insert 25. Also, as the upper wall 34 of slot 27 recedes each Wire 22 will be permitted to flex upward into engagement with the corresponding normally open contact 28 to make an electrical connection between said contact and the common insert 25.

When winding is de-energized, spring 16 will bias the armature 14 to a release position defined by contact of the lower edge of actuator 26 with a hard rubber stop 35. As armature 14 moves the actuator 26 downward, wall 34 will push each wire 22 away from its corresponding normally open contact 28; and, as wall 33 is concurrently lowered, each wire 23 will be permitted to make contact with its corresponding normally closed contact 29.

It may here be noted that rough adjustment of the position of the core 11 is effected by screws 13. Stop 35 is carried by a screw 36 that is adjustably positionable within a bore in base 12 in order to permit accurate adjustment of the travel x of the armature.

If preferred, conventional single wire-type contact members may be used in lieu of the turn wire-type permissive make contact members 20 herein illustrated. This could readily be accomplished, in effect, by eliminating wire 22 and elongating the contact point end of contact 28 in a downward direction toward contact 29. In such case, the wire 23 would be pulled upward by the actuator into contact with a normally open contact 28 (as modified) upon energization of the winding 10.

The advantages of the present invention can best be appreciated by a comparison of the diagrammatic showings of FIGS. 2"and 3.

In relays heretofore proposed and diagrammatically illustrated in FIG. 3, an armature 14' and each contact member 20' are pivoted or fulcrumed at their respective adjacent ends at and 24', respectively. To increase the degree of permissible movement of the contact members 29, the actuator 26' must be moved farther creased, the gap between the center leg of the core and the armature increases and thus increases the operate time of the relay." Also, more turns must be included in -thefwindingto provide the additional pulling power needed; and'because the armature travel x is relatively "great, the final velocity of the armature will be relatively high, resulting in greater contact bounce and hence greater wear of the actuator by the contact members, as will be 4 understood from subsequent description of the improved relay.

By way of contrast, in the improved relay constructed according to the present invention and shown in FIGS. 1 and 2, the armature 14 and each contact member 20 are rockably supported near their non-adjacent ends, such that as the actuator 26 is positioned farther from the fulcrum point 15 of the armature, it will be positioned closer to the fulcrum points 24 of the contact members. With this arrangement, and with the actuator 26 positioned near the free end of the armature and about half way along the wires 22, 23, any predetermined requisite degree of permissible movement of each contact member can be obtained with a considerably smaller degree of movement of the armature. In other words, the desired degree of permissible movement of the contact members can be effected with smaller air gaps between the center leg of the core and the armature than is permissible in the prior art arrangement shown in FIG. 3. For example, assuming distance x to be .012 inch, and the actuator 26 to be appropriately positioned to move .009 inch .and act at about the mid point of each contact member 20, the distance y corresponding to the degree of permissible movement of the contact members will be .018 inch.

It will thus be seen that slight reductions in the air gap between the armature and center leg of the core will result in significant reductions in the dynamic portion of the operate time of the relay, because such dynamic portion varies inversely as the square of the gap. Also, reduction of this gap renders the electromagnet more efficient; in other words, it has more pulling power. Moreover, since the actuator 26 acts on the contact members 20 at points which are somewhat nearer to the fulcrum points 24 than in the prior art arrangements, there is a lesser degree of relative movement between the actuator and contact members and hence less rubbing and wear of the actuator by the contact members. Finally, since the extent of necessary armature travel x is reduced, the armature has a somewhat lower final velocity upon attainment of its make and break limit positions; and this desirably reduces the number and amplitudes of the vibratory oscillations of the armature and correspondingly reduces the amount of saw-like rubbing of the actuator by the contact members.

Thus, a relay constructed in accordance with the present invention not only operates faster than relays of types heretofore proposed, but also has a longer useful life because of the reduction in the various factors which cause wear of the actuator.

While the invention has been particularly shown and described .with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention. What'is claimed is:

1. An electro-magnetic relay comprising an electromagnet, an armature and at least one contact member disposed generally parallel to each other, an actuator connected to the armature and providing a lost-motion type operating connection between the armature and each such contact member, means for fulcruming the armature adjacent its one end, and means for fulcruming each contact member adjacent its end remote from the fulcrum point of the armature such that as the actuator is positioned farther from the fulcrum point of the armature it will be positioned closer to that of each contact member, said actuator being positioned nearer the free end of the armature than to the fulcrum point of the armature and no more than half way from the fulcrum point of each contact member to the free end of the latter such that upon energization of the electro-magnet, the armature will be attracted towards the latter and through the actuator effect movement of each contact member from a normal position to an energized position, whereby to produce a mechanical advantage that will provide a smaller value of air gap between the armature and electro-magnet than degree of movement of each contact member.

2. A relay according to claim 1, including spaced normally open and normally closed contact points, and wherein each contact member is generally U-shaped with generally parallel legs disposed at different distances from the armature, such that when the armature is released the actuator holds one of said legs away from the normally open point and the other leg floats in an elongated slot in the actuator and is inherently biased into contact With the normally closed point, and when the armature and actuator are attracted toward the electro-magnet said one leg floats within the slot and is inherently biased into contact with the normally open point and the actuator holds the said other leg away from the normally closed point.

3. An electro-magnetic relay comprising an E-type core, an armature, means for fulcruming the armature adjacent the end of one outer leg of the core, spring means to normally space the free end of the armature a predetermined distance from the end of the other outer leg of the core, at least one movable contact member, means for fulcruming each contact member at a place near but spaced from the end of said other leg and having a free end extending generally toward said end of said one leg in spaced relation to the armature, and an actuator connected to the armature intermediate its ends and having a lost-motion connection with each contact member intermediate the ends thereof to provide an operating connection therebetween, said actuator being positioned nearer the free end of the armature than to the fulcrum point of the armature and no more than half the distance from the fulcrum point of each contact member to the free end thereof such that upon energization of the relay, the armature will be attracted toward the center leg of the core and through the actuator etfect movement of each contact member from a normal position to an energized position, whereby to produce a mechanical advantage that will provide a smaller value of air gap between the armature and center leg than degree of movement of each contact member.

4. A relay according to claim 3, wherein a plurality of contact members are provided which are spaced sideby-side at substantially equal distances from the armature.

References (fitted in the file of this patent UNITED STATES PATENTS 2,241,838 Wilson May 13, 1941 2,831,939 Alizon et a1 Apr. 22, 1958 2,919,326 Greenblott et a1. Dec. 29, 1959 2,924,684 Claesson Feb. 9, 1960 2,997,560 Callaway Aug. 22, 1961 3,014,103 Moran et al. Dec. 19, 1961 3,061,765 Hess Oct. 30, 1962 

1. AN ELECTRO-MAGNETIC RELAY COMPRISING AN ELECTROMAGNET, AN ARMATURE AND AT LEAST ONE CONTACT MEMBER DISPOSED GENERALLY PARALLEL TO EACH OTHER, AN ACTUATOR CONNECTED TO THE ARMATURE AND PROVIDING A LOST-MOTION TYPE OPERATING CONNECTION BETWEEN THE ARMATURE AND EACH SUCH CONTACT MEMBER, MEANS FOR FULCRUMING THE ARMATURE ADJACENT ITS ONE END, AND MEANS FOR FULCRUMING EACH CONTACT MEMBER ADJACENT ITS END REMOTE FROM THE FULCRUM POINT OF THE ARMATURE SUCH THAT AS THE ACTUATOR IS POSITIONED FARTHER FROM THE FULCRUM POINT OF THE ARMATURE IT WILL BE POSITIONED CLOSER TO THAT OF EACH CONTACT MEMBER, SAID ACTUATOR BEING POSITIONED NEARER THE FREE END OF THE ARMATURE THAN TO THE FULCRUM POINT OF THE ARMATURE AND NO MORE HALF WAY FROM THE FILCRUM POINT EACH CONTACT MEMBER TO THE FREE END OF THE LATTER SUCH THAT UPON ENERGIZATION OF THE ELECTRO-MAGNET, THE ARMATURE WILL BE ATTRACTED TOWARDS THE LATTER AND THROUGH THE ACTUATOR EFFECT MOVEMENT OF EACH CONTACT MEMBER FROM A NORMAL POSITION TO AN ENERGIZED POSITION, WHEREBY TO PRODUCE A MECHANICAL ADVANTAGE THAT WILL PROVIDE A SMALLER VALUE OF AIR GAP BETWEEN THE ARMATURE AND ELECTRO-MAGNET THAN DEGREE OF MOVEMENT OF EACH CONTACT MEMBER. 